A magnetic detecting device having a large ΔRA value is provided. A free magnetic layer has a three layer structure in which a CoFe layer, a NiaFeb alloy layer (here, a and b are represented by at %, and satisfy the relationship of 47≦a≦77 and a+b=100), and a CoFe layer are laminated.In addition, pinned magnetic layers have heusler alloy layers, which are made of a heusler alloy such as a Co2MnGe alloy. Accordingly, the product ΔRA of a magnetic resistance variation ΔR of the magnetic detecting device and an area A of the device can have a value of 5 mΩμm2 more.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A magnetic detecting device comprising: a multilayer film, which has at least one pinned magnetic layer magnetized in one direction and a free magnetic layer formed on the pinned magnetic layer with a nonmagnetic material layer therebetween, and in which a sense current flows in the direction perpendicular to the plane of each layer forming the multilayer film, wherein the free magnetic layer includes a Ni a Fe b alloy layer (a and b are represented by at %, and satisfy the relationship of 47≦a≦77 and a+b=100), the pinned magnetic layer includes a Co 2 YZ alloy layer (Y is one or more elements of Mn, Fe, and Cr, and Z is one or more elements of Al, Ga, Si, Ge, Sn, In, Sb, Pb, and Zn), and wherein the Co 2 YZ alloy has a Heusler structure.
2. The magnetic detecting device according to claim 1 , wherein a product ΔRA of a resistance variation and an area of the device has a value of 5 mΩ/μm 2 or more.
3. The magnetic detecting device according to claim 1 , wherein the free magnetic layer has a three layer structure in which CoFe layers are laminated on the upper and lower sides of the Ni a Fe b alloy layer, respectively.
4. The magnetic detecting device according to claim 1 , wherein the pinned magnetic layer is provided above the free magnetic layer.
5. The magnetic detecting device according to claim 1 , wherein the pinned magnetic layer is provided below the free magnetic layer.
6. The magnetic detecting device according to claim 1 , wherein the nonmagnetic material layer and the pinned magnetic layer are provided below the free magnetic layer, and another nonmagnetic material layer and another pinned magnetic layer are also provided above the free magnetic layer.
7. The magnetic detecting device according to claim 4 , wherein an antiferromagnetic layer overlaps the pinned magnetic layer.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
February 28, 2006
March 10, 2009
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